The invention relates to a system for heating condensate water by extracting residual heat of a power plant through a heat pump, belonging to the technical field of thermoelectricity. The system comprises a boiler, a steam turbine, a condenser, a condensate water pump, a low-pressure bleeder heater, a deaerator, a high-pressure bleeder heater, a water-cooling tower, a water-circulating pump, a chemical water treater, a heat pump unit, a heat exchanger and a by-pass valve, wherein the boiler, the steam turbine, the condenser, the condensate water pump, the low-pressure bleeder heater, the deaerator and the high-pressure bleeder heater form a loop; and the condenser, the water-cooling tower, the heat pump unit, the heat exchanger and the by-pass valve form one loop. The invention can recover the heat energy in the cooling water of the power plant, reduces the evaporation capacity of the cooling circulating water, and saves energy and water.